Not just A fossil. A contiuum of fossils and the relationship between one and the next. If you lined up the progression on a table you might argue that each could be the same species as the one to the left and the one to the right in every case. But jump 2 to the left or right and that is not likely and jump 3 and the differences are large.<quoted text>
So if a fossil over laps another fossil there are no missing transitionals?
Furthermore this gradation of differences starts with specimens measurably more similar to typical ape morphlogy and gradually moves to measurably more human morphology.
And of course, dating of this row of specimens will also show the most apelike to be the oldest and the least to be the youngest.
This is all as evolution predicted before the first was found, a perfect case of a theory making valid observable predictions. A creationism neither predicted nor can explain it.